Macular degeneration causes much serious reduced vision in older adults. This disease is characterized by drusen on Bruch's membrane and clinically detectable changes in the retinal pigmented epithelium. The pigmented epithelium is normally attached to Bruch's membrane and is clinically affected early in this disease. Drusen represent the localized loss of that normal association. Their composition is unkown. Although Bruch's membrane contains basement membrane layers identifiable ultrastructurally, not all basement membranes are identical. Basement membranes from different organs vary not only in the proportion of common components but also contain unique proteins that may determine their tissue-specific properties. Whether Bruch's membrane contains such unique components is unknown. Knowledge of the contribution of normal and diseased pigmented epithelium to Bruch's membrane, drusen and the extracellular matrix will advance our understanding not only of age-related maculopathy, but also of such diseases as retinitis pigmentosa and other retinal degenerations. Using human autopsy material in organ culture, we will investigate the composition of Bruch's membrane from normal eyes, looking for regional (e.g., macular vs. peripheral) and age-dependent differences, and compare these findings with those from diseased (e.g., drusen-bearing) eyes. In addition, using a cell culture system, we will study the contribution of the pigmented epithelium to Bruch's membrane. These studies will emphasize the biochemical detection, characterization and quantitation of Bruch's membrane-extra-cellular matrix components. Radiolabled and unlabeled matrix macromolecules will be extracted sequentially and the component collagens and glycoconjugates studied. Characterization of these components by chromatographic and enzymatic procedures will be supplemented by immunofluorescence and ultrastructural techniques using antibodies already available and those which we will produce against other Bruch's membrane components. Quantitation of these components will be by enzyme-linked immunoassays and radioimmunoassay. Characterization of extracellular matrix components in human eyes of various ages with and without disease and information on the ability of normal and diseased pigmented epithelium to synthesize these components should help elucidate the basis of blinding diseases.